They work great as long as you use the correct size tubing and fittings. Also I prefer the harder plastic tubing over the really soft type. We have push connectors all over the equipment at work. The worst combination is when someone tries to use 6mm tubing in a 1/4" connector. It'll blow out eventually.
'03 KTM 450EXC
"If you know what you're doing, then you aren't learning anything." - A. Lincoln